What question did this study set out to answer?

This study aims to determine how varying levels of corn flour influence the nutritional value and digestibility of rice straw through co-extrusion.

June 26, 2026Open Access

Varying Corn Flour Inclusion Levels Modulate Fiber Fraction Degradation and Nutritional Value of Rice Straw via Co-Extrusion

Key Points

This study aims to determine how varying levels of corn flour influence the nutritional value and digestibility of rice straw through co-extrusion.
Co-extrusion of rice straw with varying corn flour levels (0% to 40%) using a twin-screw extruder.
Analysis of chemical composition and in vitro dry matter digestibility (IVDMD) using a pepsin-cellulase assay.
Regression analysis to ascertain the relationship between corn flour inclusion and IVDMD.
RS60:C40 formulation showed a 49.5% increase in IVDMD compared to RS100 (p < 0.01).
Cellulose decreased by 60.6% in RS60:C40 post-extrusion (p < 0.05).
Significant positive correlation between IVDMD and water-soluble carbohydrates (r = 0.96, p < 0.001).

Abstract

Rice straw, one of the most abundant agricultural residues worldwide, remains significantly underutilized as a ruminant feed source owing to its intrinsic lignocellulosic recalcitrance. This study investigated the effects of co-extruding rice straw with varying proportions of corn flour on nutritional composition and in vitro digestibility for ruminant nutrition. Extrusion was conducted using a twin-screw extruder at 180 °C barrel temperature, 5 MPa pressure, and 50% feed moisture content. Five corn levels were formulated on a dry matter basis: pure rice straw (RS100); three blends with increasing corn flour inclusion: RS75:C25 (75% straw + 25% corn flour), RS67:C33 (67% straw + 33% corn flour), and RS60:C40 (60% straw + 40% corn flour); and pure corn flour (C100) as a control. Chemical composition including neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), cellulose, hemicellulose, water-soluble carbohydrates (WSC), and starch was analyzed. In vitro dry matter digestibility (IVDMD) was determined using a pepsin-cellulase assay. Regression analysis within the practical 0–40% corn flour inclusion range revealed a significant quadratic relationship with IVDMD (R2 = 0.999, p 0.05). Scanning electron microscopy (SEM) of the RS60:C40 formulation revealed that, unlike the intact fibrous structures observed prior to extrusion, post-extrusion samples exhibited extensive disruption of the fibrous matrix. Pearson correlation analysis further supported these findings, showing strong positive correlations between IVDMD and WSC (r = 0.96, p < 0.001) and strong negative correlations between IVDMD and NDF (r = −0.95, p < 0.001). In conclusion, extrusion generally increased IVDMD and WSC while reducing fiber fractions, with the effect depending on corn level. Co-extrusion with 40% corn flour effectively enhanced the nutritional value of rice straw, offering a viable strategy for producing a more digestible ruminant feed.

Read Full Paperexternally

AIに質問

Bookmark

View Full Paper